Boris Johnson has said he is “cautiously optimistic” about the prospects for a deal at crucial international talks in Glasgow to curb global warming.

On the second day of the Cop26 summit, the Prime Minister welcomed a series of announcements by the assembled leaders on deforestation and emissions.

But he stressed there was still a long way to go if they were to get an agreement that would keep alive the prospect set out in the Paris Agreement of restricting world temperature rises to 1.5C.

Ahead of the summit, Mr Johnson suggested that humanity was 5-1 down at half-time in the battle against climate change.

But speaking at a press conference on Tuesday, he said: “We’ve pulled back a goal, or perhaps even two, and I think we are going to be able to take this thing to extra-time, because there’s no doubt that some progress has been made.”

He added that while the “doomsday clock is still ticking”, they now had a bomb disposal team on site and “they’re starting to snip the wires – I hope some of the right wires”.

His sense of hope was echoed by US President Joe Biden, who said: “I can’t think of any two days more has been accomplished dealing with climate than these past two days.”

He said China’s President Xi Jinping and Russian President Vladimir Putin had made a “mistake” in staying away that would cost them influence around the world.

“We showed up. By showing up, I think we had a profound impact on the way, I think, the rest of the world is looking at the United States and its leadership,” he told a news conference before heading back to America.

“They (China) have lost the ability to influence people around the world and here in Cop. The same way I would argue with Russia.”

The Prime Minister welcomed commitments made by scores of leaders attending the summit to halt and reverse deforestation and to cut methane emissions.

In particular, he highlighted a pledge by Indian prime minister Narendra Modi to slash his country’s carbon emissions by switching half its power grid to renewable sources.

He also acknowledged, however, that the issue of climate finance had yet to be resolved – despite a 10 billion dollar (£7.3 billion) commitment from Japan over five years.

Mr Johnson said the richer nations were still behind on a commitment first made at Paris in 2015 to transfer 100 billion dollars (£73 billion) a year to developing countries to support sustainable development and mitigate the inevitable effects of global warming.

“What I’ve been asking for, as you know, is action on coal, cars, cash and trees, and after just a couple of days we can certainly begin to tick three of those boxes,” the Prime Minister said.

Mr Johnson was returning to London after end of the two-day leaders’ event which opened the summit, but he made it clear he would continue to be engaged.

In a message to the remaining teams who will get down to the task of detailed negotiations, he said: “The eyes of the world are on you – the eyes of the British Government and all the other governments that care about this – and we have got your numbers.”

Downing Street said the talks were beginning to gather “significant momentum” but cautioned that there was still some difficult negotiations ahead.

“What is vital is that we continue to use the entire two weeks of Cop to push forward to get success at all levels,” the Prime Minister’s official spokesman said.

“There will be some very difficult negotiations in the coming days. We are not complacent. This is not a done deal by any means.”

The scale of the differences were underlined by Mr Modi demanding that developed countries make one trillion US dollars in future climate finance “as soon as possible today”.

Mr Johnson said it was important not to get caught up in a mood of “exaggerated enthusiasm” generated by a gathering like Cop26 and to guard against “false hope”.

However, US climate envoy John Kerry said he had never seen such urgency, commitment or energy in climate talks.

“We’ve already achieved an enormous amount at Cop, in ambition, money, a whole bunch of new initiatives,” he said.

“Frankly, we’re a day and a half into this and I’ve seen more energy and more commitment and more urgency than I’ve ever seen, and I’ve been doing this since 1988.”